Anaerobic condition is necessary for silage making;this condition limits the activity of aerobic microbes and promotes
lactic acid fermentation. However, when the silo is opened,the anaerobic environmentis changed to an aerobic one. Such
a condition will provide an opportunity for dormant aerobic microorganisms to multiply, and make the silages unstable.
Aerobic deterioration is a process that results in biochemical and nutrient loss. Many workers have found that aerobic
deteriorationresultedfromthe activity of yeasts andmoldsutilizing residual water-soluble carbohydrates (WSC) andlactic
acid, resulting in withapHvalue rising, drymatter (DM)loss and energy release (Muck et al., 1991).Inaddition,the growth
of molds may produce mycotoxins, which threaten the health of humans and animals (Pahlow et al., 2003). The roles of